Factbox: The main sticking points at the U.N. climate talks

WARSAW (Reuters) - Negotiators from nearly 200 nations at U.N. climate talks in Warsaw are trying to lay the foundations for a new global treaty on climate change to be agreed in 2015, but green groups have walked out in protest at the lack of progress.

Following are the main sticking points:

WORK PLAN - The conference is meant to produce a work plan and timetable for a final deal to be secured in Paris in 2015. But the selection and wording of issues are politically sensitive. Rich countries want to emphasize future emission targets for all, and access to new emissions-trading markets, while developing nations want to play up equity, which includes rich countries paying more for emissions control because it is their industries that have historically accounted for most global warming.

LOSS AND DAMAGE - Developing nations are pushing for a new mechanism to deal with loss and damage related to climate change, but developed countries do not want there to be any new institution, fearing that it could pave the way for huge financial claims.

FINANCE - At the Copenhagen talks in 2009, rich nations promised funds of up to $100 billion a year by 2020 to help the developing world to deal with climate change, but so far the actual payments have fallen far short. Developing countries do not want to discuss new commitments for themselves until the rich have fulfilled their promises.

SHORT-TERM AMBITION - While the new treaty deals with greenhouse gas emissions after 2020, negotiators are also trying to ramp up action to cut emissions in the near term. But again, a rich-poor divide is blocking progress. Developing countries say developed nations must step up their efforts because they are historically responsible for climate change, while Australia, Europe, Japan and the United States say everyone must do more.

The talks are scheduled to end on Friday afternoon, but most observers and delegates expect them to carry on into Saturday.